Rotozoom Image Optimizer — User Manual

Faster pages through next-generation image compression. Image Optimizer compresses and converts your store's images to the modern AVIF format, optimises automatically on upload, processes your entire media library in bulk, and can keep a backup of every original.

• Free version: AVIF conversion on upload and in bulk, whitespace trim & pad-to-square, browser-based AI background removal, no daily limit.
• Pro version: adds SEO filename renaming, max image size / fixed height, and "product images only" scoping.
• Pro price: €49 / year per site, incl. VAT.

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For newcomers: what this plugin does

Photos are usually the heaviest part of an online shop, and heavy pages load slowly — which frustrates customers and hurts your ranking on Google. Image Optimizer fixes this by shrinking the file size of your images without you noticing a drop in quality, and by saving them in AVIF, a format far smaller than old JPEG/PNG files while looking just as good.

It does this automatically when you upload a new image, and it can process the thousands of images already in your store in one bulk run. Important: as soon as the plugin is active, every new upload is converted at once (trim and pad-to-square on, original replaced) and Keep originals is off by default — review the settings and turn Keep originals on before uploading or running a bulk job if you want to be able to restore originals.

Setup

1. Check your server supports modern formats

AVIF needs the right image library on your hosting (Imagick with AVIF support, or GD with AVIF support on PHP 8.1+). Most modern hosts have this; the plugin's status screen tells you what is available. If AVIF is unavailable, conversion is skipped and your images are left unchanged.

2. Choose your optimisation settings

In the plugin settings (Media → Image Optimizer) you control:

• Thumbnail format — AVIF (smallest) or WebP.
• Max image size (Pro) — a maximum width/height or a fixed height; larger uploads are scaled down.
• Trim and pad-to-square — tidy inconsistent product photos into uniform dimensions.
• Keep originals — off by default; strongly recommended, because it lets you restore at any time.
• Product images only (Pro) — limit optimisation to product images.

3. Optimise on upload, then bulk-process the rest

New uploads are optimised automatically. To handle your existing library, run a bulk optimisation from the plugin's settings page.

Feature reference

AVIF conversion

Converts JPEG/PNG/WebP/GIF source images into AVIF, the smallest modern format; thumbnails can be AVIF or WebP. The original file is replaced by its AVIF version (all current browsers display AVIF), so pages get lighter with no visual change. Transparent areas of PNG images are filled with white during conversion.

Trim, resize & pad-to-square

Cleans up product photography:

• Trim removes empty borders.
• Resize (Pro) enforces a maximum dimension or a fixed height.
• Pad to square places images on a square canvas so every product tile is consistent.

SEO filename renaming (Pro)

Renames image files to clean, descriptive, keyword-friendly names instead of IMG_4821.jpg. Descriptive filenames help images rank in Google Image search and improve overall on-page SEO.

Backup of originals

With Keep originals turned on (it is off by default), the original file is stored before any change so you can restore it later. Turn it on before your first bulk run to make optimisation safe on a live store.

AI background removal

Remove the background from product photos for a clean, catalogue-style look:

• Local (browser) removal — Free and Pro: the cut-out runs in your own browser, image by image, so the photo is not sent to Rotozoom. The first time, the AI library and model are downloaded from public sources (cdn.jsdelivr.net and huggingface.co).

Limits

• Free and Pro: no daily processing limit — you can bulk-convert your whole store on the Free plan.
• When Pro ends: SEO filename renaming, max image size / fixed height and "product images only" stop applying at once; AVIF conversion keeps working.

Free vs Pro at a glance

Feature	Free	Pro
AVIF conversion on upload and in bulk	✓	✓
Whitespace trim & pad-to-square	✓	✓
Max image size / fixed height	—	✓
SEO filename renaming	—	✓
Local AI background removal (browser)	✓	✓
Backup & restore of originals (Keep originals)	✓	✓
Images per day	unlimited	unlimited
"Product images only" scoping	—	✓

Advanced notes

• Bulk processing: bulk runs are driven from the open settings tab in your browser on every host (no WP-Cron or background requests needed) — keep the tab open until the run completes.
• Quality vs size: AVIF gives the smallest files at the same visual quality; thumbnails can use AVIF or WebP.
• Restoring: with Keep originals enabled, you can revert an image or re-run optimisation with different settings at any time.

Troubleshooting

• AVIF not generated — your server lacks AVIF support (Imagick with AVIF, or GD with AVIF on PHP 8.1+); the plugin status screen shows what is available, and your images are left unchanged.
• A bulk run stops partway — reopen the settings page and start the run again; it continues where it stopped. Keep the browser tab open for large jobs.
• Pro features stopped working — SEO renaming, max image size and "product images only" need an active Pro licence on this site; check that Rotozoom Connect is signed in to your Rotozoom account.

Pro needs the plugin downloaded from rotozoom.com: activating it installs Rotozoom Connect automatically — sign in with your Rotozoom account and Pro activates for that one site. See Installing and updating plugins.